newUI seems to have a sort of generic way of handling various error messages - they are displayed in a yellow bar at the bottom of the screen.
This does not seem to be capable of line wrapping. Any time an error message is too wide for the screen, it doesn't get wrapped, it just flows off the side of the screen. You can't read the end of it. And it also seems to screw up the display of the 'FEDORA 18-TC3 INSTALLATION PRE-RELEASE / TESTING' text at top right - until the error message goes away, that is rendered off the side of the screen too.
I've seen this with the new hostname setting code - the error message that starts "Hostname is not valid: Hostnames can only contain the characters 'a-z', 'A-Z', '0-9', '-' or '.', parts between periods must contain something and cannot start or end..." is too wide for a 1024x768 display (overflows at that point), and also with the root password setting code (the error about a password being based on a dictionary word is too wide and also overflows). I don't think the sensible response is 'make sure any error message anaconda can possibly display fits on a single line at 640x480' or anything like that, surely it makes more sense to allow them to wrap?

So I suppose with the proposed fix for this (enabling wrap) we need to be on the look out for absurdly long errors that might flow over the whole screen or something. Perhaps there should be some kind of sanity cap on total length?

Confirmed in smoke8 (tested using the 'password is based on a dictionary word' root PW set error, in French - in English it just fits on one line at 1024x768, in French it goes over). Wrapped nicely onto a second line, no apparent ill effects.